When lunging or squatting, your knees should not: A. Be out of alignment with your ankles B. Come forward past your toes C. Bend your knees to 45 degrees D. All of the above

Which accurately compares concave and convex lenses?

What is the force that opposes motion and works against the downward pull? a) friction b) gravity c) weight d) acceleration

Two steel balls, each of mass m, are welded to a light rod of length l and negligible mass and are initially at rest on a smooth horizontal surface. a horizontal force of magnitude f is suddenly applied to the rod as shown. determine (a) the instantaneous acceleration a of the mass center g and (b) the corresponding rate at which the angular velocity of the assembly about g is changing with time.